I am testing a freezer prototype and have a problem with gradual capacity loss. It is 14 cu ft reach-in freezer, hermetic R-404A 1/2HP compressor, cap tube system. After start-up the freezer reaches –20F in approximatelly 1.5hr, goes into cyccling stage around 2cycle/hr, then number of cycles decreases, and after 4-5 days the temperature does not go below –16F, with tendency of even more capacity loss. We detected oil accumulation in the evaporator, modidifed suction piping and that seems to resolve the problem with oil accumulation. There was also a small leak on the high-pressure gauge, so the gauge has been changed but we still have gradual capacity loss which becomes noticable after 3-4 days. Any suggestions, what else might be a reson what capacity loss?